North West Ambulance Service has urgently appealed for people to only call 999 for life-threatening injuries as crews were “extremely busy”.
Severe weather and hospital handover delays had caused problems, it said.
The service said since 17:00 GMT more than 600 people were waiting for ambulances in the region and 100 emergency vehicles were waiting at hospitals to hand over patients.
It pleaded with people to “think before dialling 999”.
Ged Blezard, director of operations at North West Ambulance Service, said: “Please only call 999 if someone has a serious illness or injury, you think their life is at risk and you cannot get them to hospital by any other means.
“We know there are patients waiting for our help and we are sorry that we are unable to respond as quickly as we would like.
“Please be assured that we will get to you as soon as we can.”
He said: “We cannot stress enough that our ambulance crews are reserved for the most life-threatening cases and these incidents will be prioritised.”
He urged people not to call 999 to check on ambulance arrival times as it “cannot answer this question and this blocks the line for other calls trying to get through”.
“For all other health concerns, it is likely we will direct you to alternative services, so please help us by first checking your symptoms at 111.nhs.uk and call on friends or relatives for transport if necessary,” he added.
Source: BBC